In general when using an automatic guidance/steering (AG) system, the operator defines a path which is used as a reference or guide when travelling the work area (field). The path may be stored in the system such that it can be restored manually by the operator or automatically where, for example, the system identifies the field using a global navigation satellite system (GNSS) position of the vehicle and the GPS position of the field with the predefined path. Once a path is stored, it can then subsequently be used for different machines or applications whereby settings (e.g., working width and overlap) may be adapted for each vehicle or application type (e.g., a tractor with a tillage implement or a combine). The reference path may initially be defined manually using, for example, the A/B mode, the A+ mode, the pivot mode and/or the contour mode.
In the A/B mode, the path is defined by driving from a point A to a point B defining a straight path reference line. The initial reference line is then offset according to one or more geometry settings of the machine (e.g., a width of the machine and overlapping). At the end of the field, the operator deactivates AG by manually steering, turns the vehicle, and activates AG again, wherein the AG system steers the machine along the next line.
In the A+ mode, the path is defined by driving to a point A and adjusting an angle (e.g., with reference to the cardinal directions: NORTH is 0°, SOUTH is 180°, etcetera) to define a straight reference line intersecting the point A and running at the defined angle. Headland turning in the A+ mode is similar to headland turning in the A/B mode.
In the pivot mode, the vehicle is driven around a circular arc thereby defining a circular reference path with a center and a radius. Once the vehicle completes a circle, the AG system guides the vehicle to the next (inner) circular path. There is no headland turning in this mode.
The contour mode is used in fields with curved or complex field boundaries. The vehicle is driven along a path surrounding the work area, wherein the driven path is recorded as the reference path. There is no headland turning in this mode.
With reference to FIG. 1 of the accompanying drawings, use of the contour mode to define a path is described in more detail. A major requirement for the recording of reference path line 1 is that it can be used for various applications. A reference path line RP can then be taken to define the calculated path CP and subsequent path lines SP for the respective operations. By changing application settings like working width (width of the implement or combine header) and overlap (area which is passed twice) the subsequent path lines SP can be calculated very easily. Due to the irregular field boundary especially in small structured regions (e.g. in Mid Europe), the contour mode is used more frequently.
An agricultural vehicle V is driving in the contour recording mode along the boundary 1 of a field F which is to be worked whereby a driven path 1 is recorded. At the edges 2b of field F and depending on the agricultural application (during which the path definition is recorded), the vehicle passes a curve 1a with a respective driven radius RD which may vary during recording or may be too small for other vehicle combinations (e.g., when the reference line is recorded with a small saddled broadcast seeder and the next operation is with a very long plough needing much greater turn radius).
To meet the requirement that the reference path line 1 can be used for additional, different operations, the radius RD is corrected by overriding with a standard radius RS (e.g., 10 meters) shown by the inner curved line. So a calculated path line CP (driven path 1 with amended radiuses RS) is then recorded. As a consequence, the difference between the two radiuses RD and RS results in areas which may not be worked when using the calculated path CP or subsequent path SP line. Due to liability issues this standard radius RS cannot be changed by the operator to avoid damage during automated steering.
A further disadvantage of the contour mode relates to the fact that in some applications, a corner cannot be passed by driving a curve. A combine harvester with a wide header, for example, may not be able to pass a curve as the loading of the header would be unbalanced, impacting the function of the feeder system. Furthermore, tractors with large ploughs also may not be able to pass the corners with a curve when the plough is engaged with the soil. In both of these scenarios the vehicles are forced to pass the corners with headland maneuvers.
To overcome this problem operators must abort contour mode at every corner and on subsequent path lines SP. This results in substantial manual intervention, introducing the risk of human error and compromising operational comfort and ease of use.
The above section provides background information related to the present disclosure which is not necessarily prior art.